Annular sealing ring

ABSTRACT

An annular sealing ring which is adapted to provide an airtight seal between relatively rotatable opposed concentric surfaces. The ring comprises a strip of laminated material which is folded longitudinally upon itself to provide a substantially &#39;&#39;&#39;&#39;teardrop&#39;&#39;&#39;&#39; cross-sectional configuration. The tubular portion of the ring at the forward end of the &#39;&#39;&#39;&#39;teardrop&#39;&#39;&#39;&#39; is adapted to resiliently engage one of the concentric surfaces, while the rear portion of the &#39;&#39;&#39;&#39;teardrop&#39;&#39;&#39;&#39; is adapted to be permanently secured to the other concentric surface. The laminated material from which the ring is constructed comprises a substrate of felt forming the outer bearing surface of the ring, and a coating of an elastomeric material bonded to the inner surface of the felt substrate.

United States Patent [151 3,637,224 Triplett et a1. 5] Jan. 25, 1972[54] ANNULAR SEALING RING 943,023 12/1909 Johnson ..277/34 [72]Inventors: Robert D. Triplett; Terry J. Laue, both of FOREIGN PATENTS QRAPPLICATIONS Effingham, Ill.

[73] Assignee: Fedders Corporation, Edison, NJ.

[22] Filed: Feb. 27, 1969 [2]] Appl. No.: 802,847

[52] 11.8. C1 ..277/229, 34/242 [51] Int. Cl ..F26b 25/08 [58] Field ofSearch... ...277/229, 34, 343, 233, 226,

[56] References Cited UNITED STATES PATENTS 2,832,618 4/1958 Knoll etal. ..277/34.3 2,943,874 7/1960 Valdi et a1. ....277/34.3 3,262,7077/1966 Williams ....277/34.3 2,686,747 8/1954 Wurtz et a1. .277/228 X2,892,650 6/1959 Runton ..277/227 2,906,552 9/1959 White .277/233 X3,125,346 3/1964 Poltorak ..277/34 X France ..277/34.3 Great Britain[57] ABSTRACT An annular sealing ring which is adapted to provide anairtight seal between relatively rotatable opposed concentric surfaces.The ring comprises a strip of laminated material which is foldedlongitudinally upon itself to provide a substantially teardropcross-sectional configuration. The tubular portion of the ring at theforward end of the t-eardrop" is adapted to resiliently engage one ofthe concentric surfaces, while the rear portion of the teardr0p" isadapted to be permanently secured to the other concentric surface. Thelaminated material from which the ring is constructed comprises asubstrate of felt forming the outer bearing surface of the ring, and acoating of an elastomeric material bonded to the inner surface of thefelt substrate.

6 Claims, 5 Drawing Figures PATENTED mm m mama ATTORNEY) BACKGROUND ANDSUMMARY OF THE INVENTION This invention relates to an annular sealingring suitable for preventing leakage of air between a rotating memberand an adjacent stationary member. In a preferred embodiment, theinvention is adapted to be used as a rear seal positioned between therotating clothes basket and the stationary cabinet of a householdclothes drying machine.

In modern high-capacity clothes dryers, it is common for the rear wallof the clothes basket to also form the forward face of the blowerhousing. This being the case, it is necessary to position an annularseal between the rotating basket and the stationary cabinet to insurethat the air directed from the fan passes through the openings providedin the basket rear wall.

To provide a suitable seal for this purpose, it has been proposed toextend a close fitting steel cylindrical band across from the basket tothe stationary blower housing to minimize the clearance and therebyreduce air leakage. This construction is normally unsatisfactory,however, since the distance between the blower housing and basket issubject to wide variation, particularly during rotation of the basket.

Prior attempts to provide an interengaging seal between the two surfaceshave not met with success since no material has been found whichpossesses all of the required physical properties. In particular, theseal should possess sufficient resilience or deformability to readilyconform to the variations in the distance between the housing and basketduring rotation. In addition, it must also possess high temperatureresistance, have a low coefficient of friction, and be impervious toreasonable air pressure.

It is an object of the present invention to provide a seal which isadapted for use in a dryer of the described type and which possesses allof the above noted properties. It is also an object to provide a sealwhich has long life, is of simple construction, and relativelyinexpensive to manufacture.

These and other objects are obtained in the illustrated embodiment ofthe present invention by the provision of an annular sealing ringcomprising a hollow tubular body member of generally circular crosssection, the body consisting of an outer bearing surface of a polyesterfelt material, and an inner coating of an elastomeric material, such assilicone rubber, bonded to the underside of the bearing surface. Thebody is formed by first coating one side of a flat strip of the feltwith the elastomeric material, and then folding the coated side of thestrip longitudinally upon itself to provide a cross section ofsubstantially teardrop" shape. The contiguous side edges of the stripare normally secured together along the length of the strip, and the twoends thereof may also be joined to form the ring. The resulting ring hasa cross'sectional configuration which includes a forward circularportion which serves as the seal, and a flat overlapping rear portionwhich serves as a means to secure the seal to the mounting member.

Additional objects and advantages of the present invention will becomereadily apparent to one skilled in the art from the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view ofa clothes dryer which incorporates the present invention,

FIG. 2 is a fragmentary perspective view of the fan housing of the dryerillustrated in FIG. 1, the clothes basket having been removed,

FIG. 3 is a fragmentary enlarged sectional view of the seal illustratedin FIG. 1,

FIG. 4 is an end view of the laminated material from which the seal ofthe present invention is fabricated, and

FIG. 5 is a fragmentary sectional view of the finished sealing ring andillustrating its "teardrop" cross-sectional configuration.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, aseal incorporating the teachings of the present invention is illustratedgenerally at 10. As best seen in FIGS. 4 and 5, the seal 10 is formedfrom a flat strip of felt material 111 which has been coated with anelastomeric backing material 12. The strip is folded. longitudinallyupon itself, with the elastomeric material facing inwardly, to form theteardrop configuration illustrated in FIG. 5. The contiguous side edgesof the strip are usually secured together by suitable means, such as bythe illustrated stitching 13. Obviously, other means of securement, suchas stapling, gluing, or self-bonding could also be employed. The twoends of the strip may then be joined by any of the above methods to forman annular ring. The resulting cross-sectional configuration of the sealincludes a forward tubular portion which serves as a resilient bearingsurface, and a rear flat portion which provides a convenient surface tosecure the seal to its mounting structure.

In the illustrated embodiment, the outer material 11 of the sealcomprises a nonwoven fabric consisting of a web or mat of randomlyoriented fibers. Such a. material, commonly referred to as felt, hasbeen found to be particularly suitable for the above purposes since itsinherent fluffiness provides a low friction bearing surface and alsosince it is capable of forming a secure bond with the elastomericbacking material 12. Obviously, a woven fabric possessing similarcharacteristics would also be acceptable for this purpose.

It is also obvious that the substrate of outer material 11 may be madefrom a variety of suitable fibers which have the ability to withstandhigh temperatures, have a low coefficient of friction, and which areeconomically practical. In this regard, the polyester fibers such asDacron sold by du Pont or Kodel sold by Eastman Kodak have been found tobe eminently suitable. These polyester fibers are capable ofwithstanding heat up to approximately 450 F., they possess high strengthand abrasion resistance, and they have a low coefficient of friction.

The backing 12 comprises a layer of an elastomeric material bonded tothe felt substrate 11. The backing material functions to give addedresilience and strength to the felt, and also to make the material moreimpervious to the passage of air. The particular thickness of theelastomeric coating, as well as the thickness and dimensions of the feltstrip, obviously de pend upon the use to which the seal will be put.When em ployed in a clothes dryer ashereinafter further described, ithas been found that a 0.06-inch-thick felt strip and a coating ofapproximately 0.0075 inch is very satisfactory.

There are several conventional methods by which the elastomeric backingmaterial 12 may be applied to the felt substrate ll. Selection of aparticular method is influenced by the physical and mechanicalproperties of the coating and substrate, together with the associatedprocessing economics. As typical examples, the coating may be applied tothe flat felt substrate by a normal calendering operation, or by a knifeor spread coating operation. Once coated, the laminated material isnormally passed through an oven where the excess solvent, if present, isevaporated and the coating resin is cured.

The particular elastomeric material employed must have the properties ofbeing impervious to reasonable air pressure and capable of withstandinghigh operating temperatures. For example, the air pressure in a modernhigh capacity clothes dryer is approximately 0.05 pound per square inch(i.e., 1.5 inch/H O) and the operating temperature approximately 400-425F. As a particular example of a suitable backing material, it has beenfound that dimethylpolysiloxane, generally termed silicone rubber, andsold under the trademark SILASTIC" by the Dow-Corning Corporation ofMidland, Michigan, is very satisfactory for this purpose. Other siliconerubbers can be employed wherein some of the methyl groups are replacedby phenyl groups. Silicone rubbers of these types are stable at hightemperature up to approximately 550 F., have an excellent ability toadhere to felt and other fabric materials, and possess sufficientdurability, strength and flexibility.

A domestic clothes dryer which incorporates a seal embodying theteachings of the present invention is illustrated generally in FIG. 1.The dryer is provided with a cabinet having a rear wall and front wall16, and top and bottom walls 17 and 18 respectively. The front wall 16has a door 20 hinged thereto enclosing an opening defined by acylindrical flange 21 in the front wall 16. This arrangement provides anaccess to the front opening 22 of a rotatable clothes container orbasket 24 for loading and unloading clothes in the basket.

The basket is mounted for rotation about a substantially nonverticalaxis which, in the present case, is preferably horizontal. Moreparticularly, the basket is substantially cylindrical in shape, andincludes a cylindrical wall 25, a front wall 26 having the opening 22,and a rear wall 27 having a shaft and bearing assembly 28 for the basket24 and the fan or blower 40. The rear wall 27 of the basket has aconically shaped depressed portion 32 providing a mounting means in theform of a sheet metal hub 34 secured thereto as by welding. The hub isdesigned to receive a ball-like bearing 35 secured to the bearing shaft36. The shaft 36 extends rearwardly through a hollow cylindrical portionof a pulley 37 and into a supporting bracket 38 fixed to the rear wall15 of the cabinet.

The blower or fan assembly 40 includes a circular sheet metal plate 41which is secured at its center to the pulley 37. The outer circumferenceof the blower includes a plurality of radially extending blades 42twisted from the plane of the plate. The fan is confined between andenclosed by the rear basket wall 27 (particularly the conical portion 32thereof) and a duct assembly comprising a front plate 44 and rear plate45 forming a passage A. The rear plate 45 is connected across the bosses46 to the cabinet rear wall to provide a passage B for the inflow ofambient air from the vents 48 in the cabinet rear wall.

A conventional heating assembly (not shown) is positioned in a suitablehousing connected to the passage A such that the fan is effective todraw heated air into the passage A for mixture with the exterior ambientair drawn through the vents 48 and passage B. The air mixture is thenforced into the basket through the openings 50 in the basket rear wall27.

The outer circumference of the front duct plate 44 is provided with atransverse flange 44' which is bent in the manner illustrated to form acylindrical flange 51 for mounting the annular seal 10 of the presentinvention. The seal 10 may be fixed to the flange 51 by a steel band 52,or by some other conventional method such as tape, adhesive, wirestitching, and the like. The seal engages a mating annular depression 54(note P16. 3) in the basket rear wall to block the passage of airbetween the basket and the flange 51 and thereby insure that the airdirected from the fan 40 will flow through the openings 50 and into thebasket 24. The air next flows through the basket 24 in the mannerindicated by the arrows in FIG. 1 and enters the openings 60 in theupper collector duct assembly 61 which is secured to the front wall 16of the cabinet. The air then passes through a removable lint screen ortrap 62 to the exit duct 63.

The dryer incorporates a basket and fan drive assembly which includes aconventional motor 65 having a first pulley 66 connected to the pulley37 of the fan through the belt 67, and a second pulley 68 operable torotate the basket by the connecting belt 69 which surrounds and engagessubstantially the entire outer diameter of the basket 24. The motor may,if desired, be reversible and incorporate an automatically operableone-way clutch arrangement whereby rotation of the motor shaft in onedirection rotates both the fan and the clothes basket for normal clothesdrying, while rotation in the opposite direction disengages the clutchto cause the drive to the basket to be disconnected while the drive tothe blower remains operative. Further details of this drive arrangement,as well as other details of the dryer structure may be obtained byreference to copending application-Ser. No. 697,453 filed Jan. 12, 1968,now US. Pat. No. 3,447,248 issued on June 6,

While the present invention has been described for purposes ofillustration with particular reference to a domestic clothes dryer, itwill be apparent from the above disclosure that the annular seal 10could be used in other equipment where a seal is required between arotating or reciprocating member and a stationary member. The seal 10 issufficiently resilient and deformable to readily conform to thevariations in the distance between the two members and thereby is ableto insure a continuous sealing engagement. The bearing surface of theseal also possesses a low coefficient of friction, and is abrasionresistant and thus long wearing. In addition, the

unique teardrop" configuration of the seal permits it to be easilymounted on a supporting member.

We claim:

1. A resilient and deformable sealing member comprising;

a strip of laminated material folded longitudinally upon itself to forma forward portion of substantially tubular configuration and a rearportion formed by the contiguous side edges of the strip,

said laminated material comprising a fabric substrate forming the outerbearing surface of said sealing member, and a coating of an elastomericmaterial bonded to the inner surface of said fabric substrate.

2. The sealing member as defined in claim 1 wherein said fabricsubstrate comprises nonwoven polyester fibers.

3. The sealing member as defined in claim 2 wherein said elastomericmaterial is silicone rubber.

4. A sealing ring for sealing between relatively rotatable opposedconcentric surfaces, said ring comprising:

a strip of laminated material folded longitudinally upon itself to forma forward portion of substantially tubular configuration and a rearportion formed by the contiguous side edges of the strip, the ends ofsaid strip being joined to provide an annular configuration,

said forward tubular portion of said ring being adapted to resilientlyengage one of said concentric surfaces, and said rear portion beingadapted to be permanently secured to the other of said concentricsurfaces,

said laminated material comprising a substrate of low friction materialforming the outer bearing surface of said sealing ring, and a coating ofan elastomeric material bonded to the inner surface of said substrate.

5. The sealing ring as defined in claim 4 wherein said low frictionmaterial comprises nonwoven polyester fibers.

6. The sealing ring as defined in claim 5 wherein said elastomericmaterial is silicone rubber.

1. A resilient and deformable sealing member comprising; a strip oflaminated material folded longitudinally upon itself to form a forwardportion of substantially tubular configuration and a rear portion formedby the contiguous side edges of the strip, said laminated materialcomprising a fabric substrate forming the outer bearing surface of saidsealing member, and a coating of an elastomeric material bonded to theinner surface of said fabric substrate.
 2. The sealing member as definedin claim 1 wherein said fabric substrate comprises nonwoven polyesterfibers.
 3. The sealing member as defined in claim 2 wherein saidelastomeric material is silicone rubber.
 4. A sealing ring for sealingbetween relatively rotatable opposed concentric surfaces, said ringcomprising: a strip of laminated material folded longitudinally uponitself to form a forward portion of substantially tubular configurationand a rear portion formed by the contiguous side edges of the strip, theends of said strip being joined to Provide an annular configuration,said forward tubular portion of said ring being adapted to resilientlyengage one of said concentric surfaces, and said rear portion beingadapted to be permanently secured to the other of said concentricsurfaces, said laminated material comprising a substrate of low frictionmaterial forming the outer bearing surface of said sealing ring, and acoating of an elastomeric material bonded to the inner surface of saidsubstrate.
 5. The sealing ring as defined in claim 4 wherein said lowfriction material comprises nonwoven polyester fibers.
 6. The sealingring as defined in claim 5 wherein said elastomeric material is siliconerubber.